Flexible Pavement Thickness Research Articles

Average full-trailer truck equivalency factors for uphill flexible pavements in developing countries

ABSTRACT This paper presents the average truck equivalency factors for four types of full-trailer trucks on uphill flexible pavements. Rising grades of 6%,12% and 18% are considered in addition to level flexible pavements. To arrive at each truck equivalency factor for the 254 full-trailer trucks studied, the axle loads were obtained from an axle load survey using permanent weighing stations. Assuming uniform motion, the axle loads on uphill pavement were calculated for different relative height of the centre of gravity of truck above pavement taking into consideration the pull force in the hook connecting both units of each full-trailer truck. The effects on average truck equivalency factor of uphill gradient, type of full-trailer truck, relative height of centre of gravity of truck, pavement structural number and terminal level of serviceability, were thoroughly studied. The paper reveals that an increase in uphill slope causes a significant increase in flexible pavement thickness especially for steep rising grades in developing countries. For rough estimation of standard single axle load applications on uphill pavements from level pavements, overall average uphill slope factors were developed. The uphill slope factor of unity for level pavement increases by about 0.038 per each 1% increase in uphill slope.

Analisis Penggantian Material Agregat Klas A Dan B Menjadi CTRB Paket Peningkatan Jalan Muara Teweh – Benangin Menggunakan Metode AASTHO’93

Roads are one of the infrastructures that will accelerate the growth and development of an area and open up socio-economic and cultural relations between regions. Along with the progress of infrastructure, the government has developed transportation facilities, namely the improvement of the Muara Teweh - Benangin road. In the Law of the Republic of Indonesia No.38 of 2004 concerning road infrastructure, roads have an important role in realizing the development of the nation's life. The improvement of the Muara Teweh - Benangin road used the flexible pavement thickness planning with the AASTHO 1993 method, the planned road life for flexible pavement was 20 years and the traffic growth factor was 6%. Sources of data used to plan flexible pavements were obtained from the Ministry of Public Works, Directorate General of Highways - National Executive Office VII. The data derived from the documentation is CBR data of subgrade and average traffic (LHR). These data are the basis most needed in planning a flexible pavement using the AASTHO method 1993. Based on the results of the calculation of the flexible pavement thickness planning using the AASTHO method, the following comparisons are obtained: (a) the total thickness of the surface layer HRS-Base / ATB 6 cm + HRS WC 3 cm, the upper foundation layer of class A = 15 cm, and the lower foundation layer of class B = 20 cm at a cost of Rp. 35,742,463,681, with an implementation time of 265 calendar days. (b) total surface layer thickness of HRS-Base / ATB 6 cm + HRS WC 3 cm, foundation layer CTRB 35 cm, at a cost of Rp. 34,278,182,220, - with execution time of 250 calendar days, resulting in a cost efficiency of Rp. 1,464,281,462, - with a difference of 15 calendar days

Experimental Investigation into the Impact of Compaction Energy Level on Thickness of Flexible Pavement

As a means of gaining a better understanding of the impact of compaction energy levels on the thickness of flexible pavements, this study investigated samples that were 50% thicker than the standard Marshall specimen sizes. The gradations for those longer (thicker) specimens were based on the binder course gradations as specified by the Republic of Turkey’s General Directorate of Highways. To obtain reliable assessments of the thicker specimens, we compared our test results with those of a control group consisting of standard Marshall Briquettes prepared using the same materials. All specimens were compacted with 10 different compaction energy levels that were increased by fives, starting from 50 blows and ending at 95 blows. After determining their lengths, volumes and specific gravities, a special marble cutter was used to split the thick specimens into two equal parts. Those two identical specimens were identified as the "thin specimens". Subsequently, the Marshall stability test and the indirect tensile test were applied both to the standard Marshall specimen group and the thick and the thin specimen groups. The test results showed that asphalt specimens of 47 and 95 mm in height were optimally compacted after being subjected to 65 and 70 blows.

EVALUASI GEOMETRIK, KINERJA DAN PERKERASAN LENTUR JALAN RAYA GUMITIR KABUPATEN JEMBER

Gumitir highway is a class I highway as a cross road between regencies and cities (Jember - Banyuwangi). The condition of this highway field with a width of 7 meters and winding and there are slopes. This highway is passed by heavy vehicles which can cause overloading (tonnage) loading, damage to the road body. Under these conditions a geometric evaluation (of the length of the arch) and calculation of the thickness of the flexible pavement on the Gumitir highway in Jember Regency .. This study aims to (1) analyze the performance of the Gumitir highway, (2) analyze the geometric of the Gumitir highway STA 229 + 664 - STA + 019, (3) analyzing the flexible pavement conditions with the 2013 UR 20-year bina marga method, (4) analyzing the inventory of the Gumitir highway. The research was conducted using the Full Circle method to calculate the geometric conditions of the Gumitir highway and 2013 Bina Marga UR 20 method for calculating the thickness of the pavement thickness of the Gumitir highway. The results of the 2013 Bina marga pavement thickness calculation results obtained for a flexible pavement thickness of 44 cm, a 3 cm HRS WC, a 3.5 cm HRS Base, a 25 cm LPA Class A and LPA Class B 12.5 cm. The results of planning the addition of warning signs point obtained 8 electric poles, 10 street lighting lamps, 8 traffic signs (addition 8 points) and longitudinal road markings in the form of solid lines

EVALUASI KINERJA DAN TEBAL LAPIS PERKERASAN DENGAN MENGGUNAKAN METODE BINA MARGA 2013 DAN DRAINASE JALAN

Road is an infrastructure which supports and plays an important role in the transportation sector. The improvement of land transportation infrastructure can support the smooth and equitable development in regional and national levels.. Benculuk highway well known as highway of various destinations. With these conditions, it is necessary to evaluate the thickness of the flexible pavement on the road. Therefore a good handling construction of normalization, enhancement or rehalibitation is needed. It will be done optimally if the factors causing the damage are known. The problem in this research is how the performance of the Benculuk highway, how to evaluate the condition of the thickness of the flexible pavement using the 2013 UR 20-year Bina Marga method, and how to evaluate the dimensions of the road drainage channel. This study aims to (1) analyze performance on the Benculuk highway, (2) analyze the flexible pavement conditions with the 2013 UR 20-year Bina Marga method (3) evaluate the dimensions of the road drainage channel. The results of the 2013 Bina Marga pavement thickness calculation obtained a flexible pavement thickness 47.5 cm, WC AC 4 cm, AC BC 13.5 cm, LPA Class A 15 cm. The results of drainage dimensions b 0.9 m and 1.1 m are planned along 2 km of KM Genteng 6 + 400 (left) with a drainage gradient value of 60% and using cemented masonry material.

Flexible Pavement Mechanistic Response to the 2017 Indonesian Road Pavement Manual with Cement-Treated Base (CTB)

The empirical method, a method developed from experiments or experience, has historically been the usual planning method used in Indonesia for designing flexible pavement thickness. The newest pavement design manual in Indonesia, Bina Marga 04/SE/Db/2017 has introduced the mechanistic method, based on pavement responses such as strain, deflection, and stress. Research was conducted to evaluate the design chart in the manual with KENPAVE program assistance in order to know the mechanistic response for the cement-treated base (CTB) foundation. The loadings for 100%, 150%, and 200% are used to know pavement response to loading variations. Vertical and horizontal strain were reviewed as mechanistic responses. Vertical strain was used to analyse rutting, and horizontal strain was used to analyse fatigue. The research shows that as the California Bearing Ratio (CBR) value increases, the smaller the vertical strain value becomes. However, this was not the case with horizontal strain where the CBR value did not seem to influence the horizontal strain value. The added loading will increase pressure on the pavement so that compressive and tensile strains on the pavement will be higher.

Determination of bituminous overlay thickness of flexible pavement by mechanistic-empirical approach based on concentration factor

In this paper, attempts are made to formulate a methodology for determination of bituminous overlay thickness of flexible pavement by mechanistic-empirical approach based on concentration factor. The term concentration factor in this paper has been defined as a factor, which is used for determination of vertical stress by Boussinesq’s theory in a two layered system. An analytical approach for determination of concentration factor has been presented in this paper for different modular ratio defined as the ratio of elastic modulus of top and bottom layer in a two layered system. The elastic modulus of in-service pavement has been obtained by back-calculation from rebound surface deflection which has been used for determination of modular ratio. In this paper, the vertical interface stress and corresponding deflection in a two layered system has been determined for an estimated modular ratio with required overlay thickness of specified resilient modulus so that the interface deflection becomes equal to the allowable deflection for design axle load repetitions as recommended by Asphalt Institute. In this backdrop, required thickness of bituminous overlay has been obtained by solving the proposed equation using back-calculation technique by Odemark’s method. Comparative analysis of the results obtained from the present study with the findings of the Indian Road Congress (IRC) shows reasonable convergence in different load ranges.

Experimental Investigation on Design of Thickness for Flexible Pavement Subgrade Soils using CBR Approach

This paper aim’s to ensure that the transmitted stresses due to wheel load are adequately reduced, so that they will not exceed bearing capacity of the sub- grade. This present study deals with the design thickness of flexible pavements, where majority of the Indian roads are flexible pavements having bituminous layer. Earlier, due to the scarcity of cement and India went for flexible pavements with bituminous toppings. This flexible pavement is preferred over cement concrete roads as they have a great advantage that these can be strengthened and improved in stages with the growth of traffic. With a major advantage of this roads and their surfaces milled and recycled for rehabilitation. The flexible pavements are less expensive also about initial investment and maintenance. In this present study, the flexible pavement thickness is designed for both sub grade soils as per IRC:37-2001 code and its pavement thickness is calculated by California Bearing Ratio (CBR)method.

Perencanaan Tebal Perkerasan Jalan Sergang – Jembatan Jengkong (No. 243) KM 8 Batu Putih Kabupaten Sumenep

The white stone mine in Batu Putih Village is one of the natural resources located in Sumenep Regency, precisely on Sergang Street - Jengkong Bridge No. 243 Km 8. This road is the only access road to the white stone mining. The current condition of the road is damaged and interferes with the distribution process of white stones, so good thick pavement planning is needed. Planning of flexible pavement thickness and the cost of flexible pavement construction on Sergang - Jengkong Bridge No. 243 Km 8 Batu Putih, Sumenep Regency uses quantitative research. The data collection process uses two types of data, the first is primary data which includes LHR data and the second is secondary data which includes literature and literature studies. In this research the data analysis technique uses Microsoft Office Excel which is to calculate the budget plan and Autocad for drawing. For calculation procedures adjusted to SNI -1732-1989. The results of the Average Daily Traffic Survey (LHR) obtained the total number of vehicles passing through by 21164 smp. The road to be planned is 3 Km long and 4 m wide. Calculation of pavement thickness using the laston AC-WC is 2.50 cm thick and will be planned to be 4 cm thick. The planned budget (RAB) for the road planning is Rp. 2,613,171,000.00 (two billion six hundred thirteen million one hundred seventy-one thousand rupiah).

Soil Stabilization using Geosynthetic Material (Steel Fibres)

Soil stabilization is the process which involves enhancing the physical properties of the soil in order to improve its strength, durability etc. by blending or mixing with additives. The different types of method used for soil stabilization are: Soil stabilization with cement, Soil stabilization with lime, Soil stabilization using bitumen, Chemical stabilization and a new emerging technology of stabilization by Geo textiles and Geo synthetic fibers. In this study, we are making use of Steel fibers as geo synthetic material for stabilization of soil. With the introduction of Steel fibers to the soil the CBR values will improve and thickness of pavement layer also gets reduced. It also reduces the intensity of stress on subgrade. Steel fibers is such a geosynthetic material which is effectively accessible, ecofriendly and furthermore savvy. With the use of soil adjustment strategy in development the general expense gets diminished when contrasted with the normal technique for development. The Highway Research Board (HRB) order of the dirt strata like dark cotton soil and sedu soil is finished utilizing appropriate examining system, for example, Core Cutter Method. To decide the attributes like Grading by Sieve Analysis, Atterbergs Limits i.e Liquid farthest point utilizing Cone Penetration Method and Casagrande Method, Plastic breaking point by rolling the example to 3mm breadth string, Shrinkage limit utilizing Shrinkage mechanical assembly, Optimum Moisture Content and Maximum Dry Density utilizing Standard Proctor Test and furthermore California Bearing Ratio by leading CBR test. The pavement thickness was designed using pavement design catalogues published by IRC SP:20-2002. The estimation for the road is done by considering the item such as Jungle Cutting, Earthwork Excavation for Roadway and Drains, compacting and grading etc., as per SR 2016-17, PW, P and IWT circle Dharwad and suggestion of specification for the mixture of Steel fibers as Geo Synthetic material for stabilization using CBR value by CBR Test and Shear strength using Unconfined Compression Test. The different tests were conducted in order to determine the different characteristics and properties of the black cotton soil and obtained with following results. The liquid limit of the soil with addition of Steel fibers was found to be decreasing when compared to liquid limit of soil alone. The plastic furthest reaches of the dirt diminished with the expansion of filaments. The shrinkage furthest reaches of the dirt was expanded with increment in strands. The MDD of the dirt with expansion of Steel filaments by weight of soil is observed to increment upto 0.75% after that it diminishes and the comparing OMC is diminished with expansion of strands. The shear quality of soil diminished significantly with expansion of strands. The CBR estimation of the dirt expanded significantly. The distinctive tests were led so as to decide the diverse qualities and properties of the sedu soil and acquired with following outcomes. The fluid furthest reaches of the dirt alone was observed to be 36.5%. The MDD of the dirt with expansion of 0.25%, 0.5% Steel strands by weight of soil is observed to be diminished by 0.83% and 0.75% , 1.0% Steel filaments by weight of soil is observed to be expanded by 0.11 % and 16.98% separately and the relating OMC is diminished by 15.62%, 21.87% and 33.75% individually. The shear quality of the dirt with the expansion of 0.25%, 0.5%, 0.75% and 1% of Steel strands is observed to be diminished by 38.57%, 38.57%, 35.25% and 5.85%. The CBR estimation of the dirt with expansion of 0.25%, 0.5%, 0.75% and 1.0%, Steel filaments by weight of soil is observed to be expanded. From the restricted research center investigation directed we reasoned that the 0.75% of Steel fiber can generously improve the properties of Black cotton soil. Furthermore, in this way 0.75% of Steel fiber is the ideal fiber content for dark cotton soil. The design thickness of flexible pavement before stabilization is obtained as 450mm and after stabilization is obtained as 250mm.The estimated cost for constructing flexible pavement before stabilization of soil is obtained as 4018050 Rs /Km and after stabilization of soil is obtained as 3721894Rs/Km. The estimated cost after stabilization is found to be decreased by 7.37%.

ANALISIS PERKERASAN LANDAS PACU BANDAR UDARA HUSEIN SASTRANEGARA, BANDUNG

Husein Sastranegara Airport which can be located at the heart of Bandung city nowadays has a runway with its PCN classification fixed at 50 F/C/X/T or equals to a total flexible type pavement thickness precisely on 740 mm. Nevertheless, Boeing 737-800 defines its classification at maximum state up to 51 on ACN scale. Therefore, overlay act upon runway pavement needs to be studied in order to enhance its classification. ACN/PCN is one of ICAO renowned method to determine pavement thickness, while recently FAA has developed a cutting-edge method by using a computerized program called FAARFIELD (FAA Rigid Flexible Iterative Elastic Layer Design). In accordance with the earlier issues, ICAO method analyzes the need of 1041.4 mm pavement thickness for graphical technique and 940.6 mm for analytical technique, while FAARFIELD should only require 840.8 mm pavement thickness in determining its flexible type runway due to the previous overlay act. The presented results of both methods established that runway pavement of Husein Sastranegara Airport shall be improved by an overlay layer immediately

ANALISIS PERENCANAAN OVERLAY PADA RUAS JALAN CRAKEN-NGULUNGKULON NAMBAK-NGULUNGKULON DENGAN BAHAN ACL PADA STA 0.00-13.345 KECAMATAN MUNJUNGAN KABUPATEN TRENGGALEK

Nowadays, the development of road capacity and vehicle quantity and the lack of optimal traffic infrastructure operations are the main problems in the Nambak-Ngulungkulon Craken-Ngulungkulon road section. This road is the object of observation because the road is an integrated system of the Nambak-Ngulungkulon Craken-Ngulungkulon road network. It is necessary to analyze how the performance and the thickness of the flexible pavement layer needed. To analyze road performance and calculate pavement thickness, the writer uses the Bina Marga 2017 method with ACL material at STA 0.00 - 13,345. The results of the analysis and calculation for the geometric planning of the Nambak-Ngulungkulon Craken-Ngulungkulon road section obtained the value of surface course with the 2017 Bina Marga method of 13 cm. Overlay work on the planning age is carried out in the 15 the year with an additional layer thickness with the Bina Marga 2017 method of 3 cm. And the traffic growth rate increased by 28.65% for 10 years y.a.d.Saat ini pengembangan kapasitas jalan dan kuantitas kendaraan dan kurangnya operasi infrastruktur lalu lintas yang optimal adalah masalah utama di ruas jalan Nambak-Ngulungkulon Craken-Ngulungkulon. Jalan ini adalah objek pengamatan karena jalan tersebut merupakan sistem yang terintegrasi dari jaringan jalan Nambak-Ngulungkulon Craken-Ngulungkulon. Perlu untuk menganalisis bagaimana kinerja dan ketebalan lapisan perkerasan lentur yang dibutuhkan. Untuk menganalisis kinerja jalan dan menghitung tebal perkerasan, penulis menggunakan metode Bina Marga 2017 dengan material ACL di STA 0,00 - 13,345. Hasil analisis dan perhitungan untuk perencanaan geometrik ruas jalan Nambak-Ngulungkulon Craken-Ngulungkulon diperoleh nilai permukaan jalan dengan metode Bina Marga 2017 13 cm. Pekerjaan overlay pada usia perencanaan dilakukan pada tahun ke-15 dengan tambahan ketebalan lapisan dengan metode Bina Marga 2017 3 cm. Dan tingkat pertumbuhan lalu lintas meningkat sebesar 28,65% selama 10 tahun y.a.d.

PERENCANAAN PENINGKATAN JALAN PADA RUAS JALAN PACITAN-NGADIROJO

ABSTRACT The Pacitan-Ngadirojo road section is one of the East Java Province Roads located in Pacitan District, which includes cross-district roads. The condition of the Pacitan-Ngadirojo road segment is generally a flat road that has several bends, inclines and derivatives along the link. Passing through a number of sub-districts and villages in the Pacitan Regency area which has right and left sides, there are settlements, agricultural land, plantations, gardens, rice fields, and traditional shopping places.To analyze road performance, the writer uses the method Manual Kapasitas Jalan Indonesia (MKJI, 1997), while to calculate the thickness of road pavement, we use the method Bina Marga (1987).From the results of the road performance analysis, data were obtained as follows: Degree of Saturation (DS) on the Pacitan-Ngadirojo road segment beginning in 2011 amounted to 0.047 while the performance analysis for the next 10 years obtained a DS of 0,078. This means that the level of road services on the road segment has not yet taken into account traffic actions or management, which in this case is road widening.For the calculation of pavement thickness with the Bina Marga Method the flexible pavement thickness on the Pacitan-Ngadirojo road section is 7,5 cm. Key words : Road Improvement Planing, Pavement Thickness, Degree of Saturation

Continuous real-time monitoring of flexible pavement layer density and thickness using ground penetrating radar

Static or discrete time prediction of flexible pavement asphalt concrete (AC) layer density and thickness utilizing the ground penetrating radar (GPR) has proved to be relatively accurate compared to other in-situ methods. However, the accuracy during continuous monitoring of construction has not been validated by real construction projects. This study investigated the continuous estimation of AC layer density and thickness using GPR at a construction site in Macomb, Illinois. The first test compared AC layer density and thickness for pavement segments built in two consecutive days. The second test evaluated the construction quality of pavement segments built utilizing two types of material transfer vehicles (MTV). The GPRan software and the proposed truncation algorithm were used to calculate AC layer thickness continuously. The AC layer density and thickness estimation results were compared to core data using the ALL model. The GPR estimation values were found to be reliable. Errors of thickness results between continuous GPR data and core data from two tests are approximate 3% and 6%, respectively. The density of the new pavement segments was larger than the old ones while the thickness was almost the same. The average error between continuous density predictions and core density was 3%. The two MTVs performed similarly based on layer thickness and density results.

A preliminary study of mechanistic approach in pavement design to accommodate climate change effects

Road damage is caused by some factors, including climate changes, overload, and inappropriate procedure for material and development process. Meanwhile, climate change is a phenomenon which cannot be avoided. The effects observed include air temperature rise, sea level rise, rainfall changes, and the intensity of extreme weather phenomena. Previous studies had shown the impacts of climate changes on road damage. Therefore, several measures to anticipate the damage should be considered during the planning and construction in order to reduce the cost of road maintenance. There are three approaches generally applied in the design of flexible pavement thickness, namely mechanistic approach, mechanistic-empirical (ME) approach and empirical approach. The advantages of applying mechanistic approach or mechanistic-empirical (ME) approaches are its efficiency and reliability in the design of flexible pavement thickness as well as its capacity to accommodate climate changes in compared to empirical approach. However, generally, the design of flexible pavement thickness in Indonesia still applies empirical approach. This preliminary study aimed to emphasize the importance of the shifting towards a mechanistic approach in the design of flexible pavement thickness.

Influence of clay mineralogy on the relationship of CBR of fine-grained soils with their index and engineering properties

Abstract Evaluation of California Bearing Ratio (CBR) of subgrade soils used in the design of flexible pavements is quite elaborate and time consuming. Hence, the number of test locations is reduced and as a compromise, the lowest value of CBR adopted for each stretch having nearly similar geological origin, but probably having varied soil properties. This leads to an increased overlay thickness of flexible pavement, and consequent cost of construction. This shortcoming is overcome by predicting CBR through index properties, so that requisite value of CBR can be obtained from more number of soil samples obtained at closer intervals. Hence many attempts have been made in the past to develop correlations equations to predict CBR from simple index properties and also relate it with engineering properties. However, no study has brought out the influence clay mineralogy of the soil in those correlations. Findings from this study show that, clay mineralogy of soil has a significant influence on both CBR (indirect measure of strength) and Unconfined Compression strength (UCC) (direct measure of strength), having separate relationships based on whether the soil is kaolinitic or montmorillonitic. This observed mineralogical is reasoned out based on the mechanisms controlling undrained strength of clays. The developed correlations to predict CBR would serve as a valuable tool to have independent check on the large data of laboratory evaluated CBR values in routine engineering practice.

ANALISA TEBAL PERKERASAN LENTUR DENGAN METODE SNI 1989 DAN METODE NCSA (NATIONAL CRUSHED ASSOCIATION DESIGN) PADA RUAS JALAN PENDIDIKAN KABUPATEN BALANGAN.

Along with the development of a more advanced civilization, then the existence of an adequate road transportation is preferred. To support this Balangan county government make policy / program that is handling the construction and improvement of roads, routine and periodic maintenance. The policy is to achieve a smooth road services, safe and comfortable. So that development activities in the area there is no constraint. Way to memenuhu smoothness, safety and comfort requirements would have a thickness of the layers according to the circumstances existing subgrade. On that basis then, in the final writing, the author raised the title of Flexible Pavement Thickness Analysis Methods With ISO 1989 And Methods NCSA (National Crushed Association Design) At Toll Road District Education Balangan. The purpose of the writer was to determine thick flexible pavement with ISO 1989 method and the method of NCSA (National Crushed Association Design). Based on secondary data using the ISO 1989 obtained the results of calculations for the surface layer lataston HRS-WC with 3 cm thick HRS-BASE 4 cm thick, the base layer of crushed stone class A with 20 cm thick, and a layer of crushed stone foundation below grade B with a thickness of 10 cm. With the NCSA method to get a thick layer with a thick surface layer lataston 5 cm, the base layer of crushed stone class A 10 cm thick layer of crushed stone foundation under class B with a thickness of 25 cm. Of the two methods above can be known methods NCSA at the surface layer and the base layer is thinner, but to the method NCSA foundation layer 15 cm thicker than the method of ISO 1989.

EVALUATION OF CBR USING GEOSYNTHETICS IN SOIL LAYERS

In urban areas, the service life of pavement on weaker soil subgrade affected severely due to their high compressibility and plasticity behaviour. These soils possess less strength, CBR value and have high affinity to moisture content. Also the seasonal changes affects the soil properties adversely. Stabilization techniques using geo-synthetic materials for improving properties of these types of soft subgrades. To increase the sub grade soil strength and to reduce the thickness of flexible pavement, Geosynthetics are increasingly used in wide variety of civil engineering applications. Geo- synthetics are the cost-effective ground modification materials which acts as a reinforcement and also increases the stability and bearing capacity of soil. Many researchers recommends the use of geo-synthetic material performs good results in soil stabilization. From this view, Evaluation has been made on poorly graded sand with the inclusion of go-grid, geo-textile and geo-composite materials between soil layers in different proportions. The CBR and shear parameters are determined for different combinations of subgrade thickness. The geo-engineering properties such as Atterberg limits, grain size distribution, compaction characteristics, and CBR value of poorly graded sand were evaluated and reported. To get the maximum California bearing ratio (CBR), the present study is put forward to understand the strength change in the soil with the addition of geo-synthetic materials. Such a study would be helpful in material selection based on site condition and strength gain along with economy.

STUDY ON COMPARATIVE FLEXIBLE PAVEMENT THICKNESS ANALYSIS USING VARIOUS DESIGN METHOD

Recently, there is a lot of variability in guide to design a pavement. Although all kinds method available, but still pavement suffers damage caused by unstable thickness. It is critical to determine the most appropriate pavement thickness for a given traffic level and subgrade condition. To overcome the problems, there is a need to study the comparative pavement thickness analysis using various pavement design methods so that it will be cost effective and long lasting. The input parameters in flexible pavement design are identified and have been used in obtaining different pavement layer thickness by conducting various pavement design method, that is Arahan Teknik (Jalan) 5/85 Jabatan Kerja Raya (JKR), AASHTO Method and Asphalt Institute Thickness Design Program (SW-1). Finding from this study indicate that thickness from Arahan Teknik (Jalan) 5/85 Jabatan Kerja Raya (JKR) gave better results than the others because it produced more thinner flexible pavement layer compared to the two other design method. In terms of cost, it will be more cost effective since the cost of material can be reduced.

Mechanistic road upgrade structural design evaluation using rapid triaxial frequency sweep testing and linear elastic modeling

Saskatchewan Ministry of Highways and Infrastructure employ modified Shell nomographs for flexible pavement thickness design. These modified design nomographs for typical 1970s Saskatchewan field state conditions are based on the local calibration of Shell design curves. However, the modified Shell nomographs are not applicable for the design of recycled pavement systems, particularly full depth reclamation and granular base strengthened systems. This paper presents a mechanistic based thickness design methodology using linear elastic road modeling and a field validation study based on granular base stabilization and strengthening pilot project on Control Section (C.S.) 15-11 in Saskatchewan. The mechanistic methodology of this research included triaxial frequency sweep dynamic modulus and Poisson’s ratio characterization of various strengthened materials taken from the C.S. 15-11 test sections, pavement structural modeling using linear elastic theory, and calculating critical pavement design strain responses. As demonstrated in this research, strengthened pavement structures can be evaluated and designed based on mechanistic testing and linear elastic modeling results. The modeling results revealed rutting and shoving failure concurred with the field performance observed. Predicted primary deflection responses also concurred with those quantified in the field using a non-destructive falling weight deflectometer.